LBE FREEZE and CLEANProject

The objective of this program is to verify the thermal behaviour of LBE capsule and to develop a process to clean the residual LBE on samples surfaces, with preliminary experiments between CVR (Czech Republic) and CEA (France), in order to prepare some future experimental experiments in support of GEN-IV nuclear reactors.

This experimental capsule which will be tested in the Jules Horowitz (JHR) reactor use thermal insulation between hot internal parts and JHR core cooling water. This component is considered as safety barrier to prevent active releasing into JHR cooling water. The capsule design is based on an annular structure in SS 316L material with a hole in the centre allowing cooling water to flow in, in order to reduce samples temperature. The objective of this part of the study, on a capsule mockup equipped with heating/cooling systems and instrumented, would be to understand what happened about LBE freezing (124 °C) when scram occurred, as LBE volume is increased when freezing.

The second part of the study would be the development of a chemical process to dissolve the residual LBE on samples from the irradiation capsule. Different ways could be checked such as carbonation, acidification, hydrolysis (+additives) cleaning…. Taking in account the composition effluents generated by the process in order to respect the compatibility with nuclear facilities operations.

Based on the state the art, two objectives are proposed:
The first one on the LBE freezing is to determine the effect of a fast freezing of the JHR capsule mockup on the solidification of LBE and measure the stress on the mockup structure. Using a representative geometry of JHR MICA-shape type – central part mockup, the tests will be performed in CVR site and the post-test examinations realized on CEA site.

The second one on the cleaning procedure is to investigate a chemical cleaning process (chemical treatment, acid hydrolysis…) on samples taken from the LBE wetted mockup. The test and post examinations will be performed on CVR site and the chemical analysis of the effluents realize on CEA site. It will be also interesting to know the compatibility of those effluents with nuclear facilities operation.

The outcome of this test is to have an experimental characterization of the stress due to the expansion of LBE in the JHR irradiation capsules during its cooling (and solidification) and to propose a method to remove the residual LBE wetting on the irradiated metallic samples (before analysis).